It looks like you are using a version of Firefox 3.6.6 from the Ubuntu repository and not the "official" version from Mozilla. The Ubuntu Firefox Modifications 0.9rc2 extension comes from Ubuntu, and isn't in the "official" versions. You might want to visit the Ubuntu support forum to find out how to change that feature which was added to Firefox by that extension - http://ubuntuforums.org/ - or you can disable that extension and see what changes. I think those buttons will reappear but I don't know what else might change that you may not like.

I am running 10.04 Lucid Netbook with the Ubuntu version of Firefox 3.6.6 and that extension, on my EeePC 900, and actually like that feature on this small 9" screen. I haven't tried disabling that 0.9rc2 extension so I don't know what else that extension modified in Firefox.

Thank you for that comment, I will look into getting the standard version. I discovered the source of the problem myself by accident.

The View Menu item, Full Screen was all I needed to restore the controls. I am not sure how it resized, but others might find this setting frustrating.